Studies of the Terrestrial Atmosphere

陆地大气研究

• 批准号: 0637433
• 负责人: Tom Slanger
• 金额: $ 50.95万
• 依托单位: SRI International
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-15 至 2012-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0637433&HistoricalAwards=false
• 关键词: Studies; Terrestrial; Atmosphere

This project combines observational and laboratory investigations of mesospheric and thermospheric oxygen chemistry. The first task is elucidation of the chemical mechanism that is responsible for the large variability in the sodium D2/D1 line ratio in the nightglow. Although a newly recognized phenomenon, it is now evident from repeated measurements in different locations and environments that the ratio represents a window into the mesospheric chemistry that links Na, NaO, O(3P), O2, and O3. It appears likely that the variability reflects the changing [O]/[O2] ratio within the sodium nightglow region, and thus represents a probe of this ratio. The second task involves laboratory studies of the loss rate coefficients of O2(b) molecules over the vibrational range of v = 3-8 range, using both O2 and O-atoms as colliders. This will lead to an improved understanding of the atmospheric production rates of these molecules and their production mechanisms. The third task is an investigation of the O2 Atmospheric band emissions seen in the mesosphere. It has been observed that the various vibrational levels do not vary in concert. The project will test the hypothesis that the emission intensity ratios can be related to variations in the mesospheric O-atom density. The fourth task seeks to explain a discrepancy between theory and observations for the oxygen red line emissions and those from the nitrogen doublet at 520 nm as they decay throughout the night. When the emissions are most intense in the early evening, there is a substantial difference between the observed and modeled intensity ratio, the red lines being more intense with respect to the nitrogen emissions than predicted. The project will carry out further measurements and data evaluations to understand the source of this difference. The broader impacts of these studies include the support of a postdoctoral scholar and contributions to other disciplines; for the latter, the O2 laboratory studies, which investigate the lower vibrational levels of the lower O2 electronic states, are of direct relevance to O2 COIL laser studies, to plasma etching, and to non-equilibrium processes in gas discharge system, while the sodium study will lead to important insights into the chemistry of meteor trails.

该项目结合了对中间层和热层氧化学的观测和实验室研究。 第一个任务是阐明的化学机制，是负责在钠的D2/D1线比在夜光大的变化。 虽然这是一个新认识的现象，但从不同地点和环境的重复测量中可以明显看出，该比率代表了一个窗口，可以了解Na，NaO，O（3 P），O2和O3的中间层化学。 这种变化很可能反映了钠夜辉区域内[O]/[O2]比值的变化，因此代表了对该比值的探测。 第二个任务是利用O_2和O原子作为碰撞器，在实验室研究了O_2（B）分子在v = 3-8的振动范围内的损失率系数。 这将导致更好地了解这些分子的大气生产率及其生产机制。 第三项任务是调查在中间层看到的O2大气带排放。 已经观察到，各种振动能级并不一致地变化。 该项目将检验发射强度比可能与中间层氧原子密度的变化有关的假设。 第四项任务旨在解释氧气红线发射和520 nm处氮双峰发射的理论和观测之间的差异，因为它们在整个晚上都在衰减。 当排放在傍晚最强烈时，观测到的和模拟的强度比之间有很大的差异，红线相对于氮排放比预测的更强烈。 该项目将进行进一步的测量和数据评估，以了解这种差异的来源。 这些研究的更广泛的影响包括博士后学者的支持和对其他学科的贡献;对于后者，研究较低O2电子态的较低振动能级的O2实验室研究与O2 COIL激光器研究、等离子体蚀刻和气体放电系统中的非平衡过程直接相关，而钠的研究将导致对流星轨迹化学的重要见解。